The invention comprises (i) 5a ,17a -dihydroxy-20-ethylenedioxy -6b -methyl-pregnan-3-one and 20-ethylenedioxy-6b -methyl pregnan-3b ,5a ,17a -triol, (ii) their preparation by transketalizing a 3-acylate of 17a -hydroxy-pregnenolone to form its 20-ketal, epoxidizing this with an organic peracid to form the 5a ,6a -epoxide, and reacting this with a methyl magnesium halide to form the triol of the invention, followed if desired by chromium trioxide oxidation to the 3-ketone of the invention, and (iii) the conversion of the 3-ketone of the invention (a) by heating in acetic anhydride solution containing p-toluene sulphonic acid to 3,17a -diacetoxy-6-methyl-3,5-pregnadien-20-one, (b) by ketal cleavage and epimersation by heating in acetone solution in the presence of a mineral acid to 17a -hydroxy-6a -methyl -progesterone, which may be converted to its 17-acetate, (c) by acid-catalysed ketal cleavage at ambient temperature to the 20-one, following if desired by an acid-catalysed combined ketalization and dehydration to form 17a -hydroxy - 3 - ethylenedioxy - 6 - methyl - pregn - 5- en-20-one, (d) agitation with acetic anhydride containing p-toluene sulphonic acid to give 17a -acetoxy - 5a - hydroxy - 6b - methyl - pregnane-3, 20-dione, followed by treatment as in (c) above to give 17a -acetoxy-3-ethylene-dioxy-6 methyl-pregn-5-en-20-one, or (e) conversion to the 3-hydrazone, and boiling this in a solution of potassium hydroxide and ethylene glycol to give 17a -hydroxy-6b -methyl-pregn-4-en-20-one, which may be converted to its 17-acetate.
展开▼
